The present invention relates to a holder for thermoresponsive means; and more particularly, to a fabricated member adapted to be disposed in intimate relationship with windings of a dynamoelectric machine, and to dynamoelectric machines including a fabricated member that is especially adapted to accommodate devices of the type generally referred to as motor overload protectors.
There has been extensive prior work pertaining to mounting arrangements for thermoresponsive devices such as overload protectors for motors. For example, Dubberley U.S. Pat. No. 2,909,719 illustrates a metal strip or fin in heat exchange contact with the casing of a thermally responsive switch. Dubberly's metal strip or fin preferably is placed between overlapping or adjacent portions of first and second motor windings. This patent also teaches that thin dielectric sheet material may be provided between the metal strip or fin and winding portions adjacent thereto for electrical insulation purposes.
Pleiss, Jr., et al U.S. Pat. No. 3,131,322 (which issued Apr. 28, 1964) illustrates still another approach for disposing overload protector means in heat transfer relationship with the end turns of a motor winding. With this approach, an overload protector is accommodated in a pocket formed by a V-shaped piece of metal foil. The metal foil in turn, is disposed between adjacent winding portions, with a V-shaped insulator (formed e.g., of cellulose acetate, or MYLAR material), separating the metal foil and the winding portions adjacent thereto.
With subsequent development of the motor protector mounting art, it has been suggested that economies in the manufacture of motor stators could be accomplished by eliminating the metal foil pocket members used before, and rely instead upon dielectric sheet material to establish a pocket for a motor protector. In order to eliminate the requirement that the motor protector be tied in place in the pocket established therefore; it has also been suggested to provide a dielectric material that could be used to lock against a spade type terminal of such protector. This tab then could be relied upon to hold the protector in place.
One variation from the above is to include a dielectric material flap that is folded and positioned to establish a layer of dielectric material between the stator winding and the interconnected portions of windings and external conductors. This dielectric material flap is now of a size and shape to permit it to be folded back over such interconnected portions. Cord or twine may then be tied about the folded over flap. With this arrangement, the flap then also provides extra protection against pulling the lead wires loose from the stator windings.
Heretofore, means such as lacing or tying cord have been relied upon to hold external lead wires in a desired position relative to the winding turns and separate sheets of dielectric material have been used to provide the desired insulation between conductor connections and winding end turns.
I have found that the various approaches suggested by others as described above have certain shortcomings. Accordingly, I have devised a new and improved arrangement that is economical to manufacture, and yet is believed to be extremely reliable in practice.
For example, locking tabs provided previously have not always securely locked a protector in place and, in at least some instances, the location of entry and or locking apertures have not always been precisely located so as to properly lock a protector in place.
Accordingly, a general object of the present invention is to provide an improved protector receptacle having an improved locking flap arrangement so that the advantages of quick assembly and precision location may be obtained and yet maximum locking strength also be established and maintained.